Vane pumps

ABSTRACT

A rotor for a pump includes a rotor body, an undervane cavity defined in the rotor body configured to accept an underside of a vane, an outer surface on a periphery of the rotor body for defining overvane cavities within a liner as a function of an inner cammed surface of the liner, and a pressure balance aperture defined in the rotor body fluidly connecting the undervane cavity to at least one of the outer surface.

BACKGROUND

1. Field

The present disclosure relates to fluid pumps, more specifically to vane pumps.

2. Description of Related Art

Certain pumps include a rotor disposed within an outer liner that includes an interior cammed surface for defining cavities between the rotor and the liner of differing sizes. Rotating the rotor within the liner causes a progressive and cyclical shrinking and enlargement of the cavities therewithin, causing compression and expansion, and ultimately, an axial fluid pumping action.

The rotor of such a pump can be registered within the liner using a plurality of vanes that can move radially inwardly and outwardly relative to the rotor and define “overvane” cavities with the rotor and the liner. Such vanes can include a spring and/or other force applied to an underside thereof to continually apply a radially outward force thereto in order to maintain contact with the cammed surface of the liner.

The vanes can retract and extend from a plurality of axial “undervane” cavities. In some cases, pressure imbalance on the vanes can present a limitation on the useable life of the pump and can cause pressure instability with the overvane pumping action, causing vibration and potentially efficiency loss.

Such conventional methods and systems have generally been considered satisfactory for their intended purpose. However, there is still a need in the art for improved vane pumps. The present disclosure provides a solution for this need.

SUMMARY

In at least one aspect of this disclosure, a pump includes a liner having an inner cammed surface, and a rotor disposed within the liner and configured to rotate therein, the rotor including an undervane cavity and an outer surface for defining overvane cavities within the liner as a function of the inner cammed surface. The rotor includes a pressure balance aperture defined therein fluidly connecting the undervane cavity to the outer surface.

The pump also includes a plurality of vanes disposed in the rotor and in contact with the cammed surface within the liner, a follower portion of the vanes extending from the rotor radially outwardly and an underside of the vanes extending at least partially into the undervane cavity. The vanes circumferentially define cavities of differing sizes therebetween within the liner in conjunction with the inner cammed surface of the liner and the outer surface of the rotor.

The pump can include a plurality of pressure balance apertures defined in the rotor in communication with the undervane cavity. The pump can include a plurality of vanes and undervane cavities as describe above. It is also contemplated that the pump can include a plurality of pressure balance apertures defined in the rotor for each respective undervane cavity. The outer surface can include an axially asymmetric shape. The outer surface can include a smooth shape.

In at least one aspect of this disclosure, a rotor for a pump includes a rotor body, an undervane cavity defined in the rotor body configured to accept an underside of a vane, an outer surface on a periphery of the rotor body for defining overvane cavities within a liner as a function of an inner cammed surface of the liner, and a pressure balance aperture defined in the rotor body fluidly connecting the undervane cavity to at least one of the outer surface.

These and other features of the systems and methods of the subject disclosure will become more readily apparent to those skilled in the art from the following detailed description taken in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

So that those skilled in the art to which the subject disclosure appertains will readily understand how to make and use the devices and methods of the subject disclosure without undue experimentation, embodiments thereof will be described in detail herein below with reference to certain figures, wherein:

FIG. 1A is a perspective view of an embodiment of a rotor in accordance with this disclosure, showing vanes disposed therein;

FIG. 1B is a cross-sectional, axial end elevation view of the rotor of FIG. 1A;

FIG. 1C is a perspective, cross-sectional view of the rotor of FIG. 1A;

FIG. 2 is a perspective, cross-sectional view of the rotor of FIG. 1A showing the rotor and vanes disposed in a liner;

FIG. 3A is side elevation view of an embodiment of a vane in accordance with this disclosure, showing an aligned peak vane configuration;

FIG. 3B is side elevation view of another embodiment of a vane in accordance with this disclosure, showing an offset peak vane configuration;

FIG. 4 is a plan view of an embodiment of a port plate in accordance with this disclosure, showing a plurality of inlets and outlets; and

FIG. 5 is a cross-sectional, axial end elevation view of a pump in accordance with this disclosure, schematically showing flow due to rotation of the rotor in the liner.

DETAILED DESCRIPTION

Reference will now be made to the drawings wherein like reference numerals identify similar structural features or aspects of the subject disclosure. For purposes of explanation and illustration, and not limitation, an illustrative view of an embodiment of a rotor for a pump in accordance with the disclosure is shown in FIGS. 1A-1C and is designated generally by reference character 100. FIGS. 2-5 show other embodiments or aspects of this disclosure. The systems and methods described herein can be used to pump fluids efficiently using a vane pump.

Referring to FIGS. 1A-1C, in at least one aspect of this disclosure, a rotor 100 for a pump (e.g., pump 500 shown in FIG. 5) includes a rotor body 101 and one or more undervane cavities 103 defined in the rotor body 101. The rotor body 101 can be of any suitable shape (e.g., a hollow cylindrical shape as shown) and can include any suitable material (e.g., metal, plastic).

As best seen in FIG. 1B, each of the undervane cavities 103 is configured to accept an underside of a respective vane (e.g., vanes 109 shown disposed in rotor 100, described in further detail below) through a slot 108. The undervane cavities 103 can be defined axially in the rotor body and/or in any other suitable manner, and can be of any suitable size, diameter, and/or length.

The rotor 100 includes an outer surface 105 on and/or defined by a periphery of the rotor body 101. Referring additionally to FIG. 2, the outer surface 105 partially defines overvane cavities 215 when the rotor 100 is disposed within a liner liner 211. The shape of the overvane cavities 215 are a function of the shape of an inner cammed surface 213 of the liner 211 and the shape of the outer surface 105.

In certain embodiments, the outer surface 105 can include an axially asymmetric cross-sectional shape and/or any other irregular shape (e.g., polygon as shown). It is also contemplated that the outer surface 105 can include a smooth cross-sectional shape (e.g., circular). Any suitbale shape and number of undervane cavities 103 is contemplated herein.

Referring to FIG. 1C, the rotor 100 further includes one or more pressure balance apertures 107 defined in the rotor body 101 which provide fluid communication from the undervane cavity 103 to one or more of the outer surfaces 105/cavities 215. The pressure balance apertures 107 can be of any suitable size or shape. Also, any suitable number of pressure balance apertures 107 can be included in the rotor body 101.

For example, as shown, the rotor 100 can include a plurality of pressure balance apertures 107 defined in the rotor 100 in communication with each undervane cavity 103 or in any other suitable combination. The plurality of pressure balance apertures 107 can be spaced in any suitable manner.

Referring additionally to FIGS. 3A-5, in at least one aspect of this disclosure, a pump 500 includes a liner 211 and a rotor 100 as described above disposed within the liner 211 and configured to rotate therein. As described above, the liner 211 can include an inner cammed surface 213 of any suitable cammed shape.

The pump 500 also includes a plurality of vanes 109 disposed in the rotor 100 and in contact with the inner cammed surface 213 of the liner 211. The rotor 100 can be disposed concentrically within the liner 211 in any suitable manner (e.g., via bearings).

The vanes 109 can include a follower portion 109 a extending from the rotor 100 radially outwardly and an underside 109 b of the vanes extending at least partially into the undervane cavity 103. The follower portion 109 a can include any suitable cam follower shape for following the inner cammed surface 213 of the liner 211. For example, as shown in FIG. 3A, vane 109 includes a follower portion 109 a having a peak 109 c that is aligned with an edge of the underside 109 b. In another embodiment shown in FIG. 3B, a vane 309 includes a follower portion 309 a with a peak 309 c that is offset from an edge of the underside 309 b. The peak location can affect how the resulting forces due to interaction with the liner 211 act on the vanes 109 (e.g., moment acting on the underside 109 b).

The vanes 109 can be disposed within slot 108 in any suitable manner that biases the vanes 109 to extend away from the rotor 100 (e.g., using springs attached to underside 109 b or any other suitable portion of vane 109). Vanes 109 circumferentially define and delimit overvane cavities 215 of differing sizes within the liner 211 in conjunction with the inner cammed surface 213 of the liner 211 and the outer surface 105 of the rotor 100.

Referring to FIG. 4, an embodiment of a port plate 400 for use with a pump 500 as disclosed herein is shown. The port plate 400 includes two inlet ports 401 and two outlet ports 403, however, any other suitable number of ports can be used. The port plate 400 is configured to operate adjacent to one or more axial ends of the pump 500 to facilitate pumping action. The port plate 400 can be connected to the liner 211 and is stationary relative to the rotor 100. The undervane cavities 103 can be sealed by port plate 400. It is contemplated that the other axial end of the pump 500 can be sealed with a solid plate or another port plate can be utilized.

Referring to FIG. 5, when assembled and operated, the rotor 100 can rotate within the liner 211. The vanes 109 extend outwardly until the follower portion 109 a abuts the inner cammed surface 213 of the liner 211. As the rotor 100 rotates, the vanes 109 follow the inner cammed surface 213 to change radial position. As the radial position changes, the volume of the overvane cavities 215 change between each pair of vanes 109. This changing volume changes the pressure within each overvane cavity 215. By placing an inlet port 401 at a position where the cavity 215 is expanding in volume, the pressure drops and draw fluid in. Likewise, by placing an outlet port 403 at a position where the cavity 215 is decreasing in volume, the increasing pressure will push fluid out of the cavity 215 through the outlet port 403.

Since pressure balance holes 107 are defined in the rotor 100, the pressure in the undervane cavities 103 and overvane cavities 215 is equalized. This prevents differing pressures on the follower portion 109 a and the underside 109 b of the vanes 109 which reduces vane movement, vibration, and pressure ripple. Further selecting the vanes 109 to include a desired peak location can further reduce ill effects. As a result, the pumping efficiency and lifespan of the system is improved compared to traditional systems.

The methods, apparatuses, and systems of the present disclosure, as described above and shown in the drawings, provide for pumps with superior properties including improved pumping efficiency and longer lifespan. While the apparatus and methods of the subject disclosure have been shown and described with reference to embodiments, those skilled in the art will readily appreciate that changes and/or modifications may be made thereto without departing from the spirit and scope of the subject disclosure. 

What is claimed is:
 1. A pump, comprising: a liner, wherein the liner includes an inner cammed surface; a rotor disposed within the liner and configured to rotate therein, the rotor including an undervane cavity and an outer surface for defining overvane cavities within the liner as a function of the inner cammed surface, wherein the rotor includes a pressure balance aperture defined therein fluidly connecting the undervane cavity to the outer surface; and a plurality of vanes disposed in the rotor and in contact with the cammed surface within the liner, a follower portion of the vanes extending from the rotor radially outwardly and an underside of the vanes extending at least partially into the undervane cavity, wherein the vanes circumferentially define cavities of differing sizes therebetween within the liner in conjunction with the inner cammed surface of the liner and the outer surface of the rotor.
 2. The pump of claim 1, further including a plurality of pressure balance apertures defined in the rotor in communication with the undervane cavity.
 3. The pump of claim 1, further including a plurality of vanes and undervane cavities.
 4. The pump of claim 3, further including a plurality of pressure balance apertures defined in the rotor for each undervane cavity.
 5. The pump of claim 1, wherein the outer surface includes an axially asymmetric shape.
 6. The pump of claim 1, wherein the outer surface includes a smooth shape.
 7. A rotor for a pump, comprising: a rotor body; an undervane cavity defined in the rotor body configured to accept an underside of a vane; an outer surface on a periphery of the rotor body for defining overvane cavities within a liner as a function of an inner cammed surface of the liner; and a pressure balance aperture defined in the rotor body fluidly connecting the undervane cavity to at least one of the outer surface.
 8. The rotor of claim 7, further including a plurality of pressure balance apertures defined in the rotor in communication with the undervane cavity.
 9. The rotor of claim 7, further including a plurality of undervane cavities.
 10. The rotor of claim 9, further including a plurality of pressure balance apertures defined in the rotor for each undervane cavity.
 11. The rotor of claim 7, wherein the outer surface includes an axially asymmetric shape.
 12. The pump of claim 7, wherein the outer surface includes a smooth shape. 